(1) Field of the Invention
This invention relates to novel phosphoric esters and more particularly, to phosphoric esters of the following general formula (I), and to a process for preparing same, ##STR4## in which X represents a halogen, R.sub.1 represents a linear or branched alkyl, fluoroalkyl or alkenyl group having from 1 to 36 carbon atoms, or a phenyl group substituted with a linear or branched alkyl group having from 1 to 15 carbon atoms, R.sub.2 represents an alkylene group having 2 or 3 carbon atoms, n is a value of from 0 to 30, and M represents a hydrogen atom, alkali metal, alkaline earth metal, ammonium, or an alkylamine or alkanolamine salt.
(2) Description of the Prior Art
Phosphoric esters have been widely utilized in various fields of detergents, fiber treatments, emulsifiers, rust preventives, liquid ion exchangers and medicines.
Among phosphoric esters, alkali metal salts of phosphoric monoesters are far superior to other phosphoric esters, such as alkali metal salts of phosphoric diesters, with respect to surface activity and the like properties. For instance, alkali metal salts or alkanolamine salts of monoesters between longchain alkyl alcohols and phosphoric acid are soluble in water. The aqueous solutions of these salts have very good foaming ability and detergency. In contrast, phosphoric diester salts are sparingly soluble in water and show little foaming ability but a foam-suppressing property.
On the other hand, currently employed detergents include alkylsulfates, alklybenzenesulfonates, alpha-olefinsulfonates and the like. Most of these surface active agents undergo skin irritation. In recent years, phosphoric monoester salts have been used as less irritative surface active agents.
As is well known in the art, a living body contains a number of surface active agents of the phosphoric ester type, which are called phospholipids, such as lecithin, phosphatidyl serine and have a quaernary ammonium in one molecule thereof. These phospholipids exhibit surface activity, emulsifiability, and physiological characteristics and are thus utilized in various fields. Accordingly, it is expected that substances having structures similar to those of phospholipids are less irritative against a living body than monoalkyl phosphoric ester salts. Therefore, a variety of phospholipid-like substances have been synthesized. However, the synthetic processes require, in most cases, a number of reaction steps and intended products are thus obtained only in low yield [see, for example, E. Baer et al, J. Amer. Chem. Soc., 72, 942 (1950)].
Some of the present inventors have prepared, by a simple procedure, and proposed (in Japanese patent application No. 59-39042) compounds having a quaternary ammonium salt in one molecule thereof and represented by the following formula (IV) ##STR5## in which R.sub.3 represents a saturated or unsaturated, linear or branched hydrocarbon group having from 8 to 32 carbon atoms with or without a substituent, R.sub.5, R.sub.6 and R.sub.7 are the same or different and are a saturated or unsaturated hydrocarbon group having from 1 to 4 carbon atoms, R.sub.4 represents an alkylene group having 2 or 3 carbon atoms, and m is an integer of from 0 to 50. This compound is readily prepared according to the following reaction formula in which a glycidyltrialkylammonium salt of the formula (VI) is reacted with a monoalkali metal salt of a monoalkyl phosphate (V). More specifically, dodecyl 2-hydroxy-3-N,N,N-trimethylammonio-propyl phosphate (in compound (IV), R.sub.3 =C.sub.12 H.sub.25, R.sub.5 =R.sub.6 =R.sub.7 =CH.sub.3, and m=0) has found to have good detergency and to be very low in irritation against a living body. ##STR6## in which M.sub.1 represents an alkali metal, X.sub.1 represents an anion, and R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and m have, respectively, the same meanings as defined before.
However, glycidyltrimethylammonium chloride is only one glycidyltrialkylammonium salt (VI) which is industrially available. Thus, it was difficult to industrially obtain compounds having various alkylammonio groups.
In the field of polymer science, studies have been made on the addition or modification of various functions to polymeric materials. In on such study, the impartment of functional properties of phosphoric acid groups or phosphoric esters, such as surface activity, chelating property, antistaticity and the like, to polymeric compounds have been extensively made in recent years.
The methods of introducing phosphorus compounds to polymeric compounds may be divided into the following three groups.
(1) Phosphorus compounds are blended with polymeric compounds.
(2) Reactive functional groups of polymeric compounds, e.g. hydroxyl groups, are phosphorilized.
(3) Phosphorus compounds serving as monomers are polymerized.
However, the method (1) is disadvantageous in that phosphorus compounds used are apt to separate from polymer compounds such as by exudation. The method (2) has the drawback that limitation is placed on the phosphorizing agent and phosphorization cannot be effected as desired. Accordingly, there is a demand of development of phosphorus compounds, used as monomers in the method (3), e.g. phosphoric esters having polymerizable groups.
Moreover, in the field of polymer films which are one of applications of polymers, studies have been extensively made on artificial films or membranes having functions of a living membrane, e.g. formation of a section and a selective transport function for a substance. These films or membranes are intended to be applied to diverse fields of engineering, medical science, pharmacy and the like. The difference between a living membrane and an artificial polymer membrane resides in that the living membrane has such a structure that the molecules are systematically oriented and, for example, a bimolecular layer structure is formed. This orientation is ascribed to the physical properties of phospholipid molecules, which are constituents of a living membrane, or the properties of self-assembling and organizing the molecules inherent to so-called amphiphilic compounds having both hydrophobic and hydrophilic groups. Accordingly, when a monomer for use as a material for membranes is taken into account, attention has been paid, more or less, to not only to chemical properties of the monomer, but also physical properties, such as surface activity and self-organizability. To this end, a number of phosphoric ester monomers having such properties as surface activity, affinity for living bodies and the like, have been synthesized, with a difficulty in industrially obtaining such monomers.